Grunt had to be quite a soldier to qualify for the G.I. Joe team. He graduated Advanced Infantry Training school in the top ten of his class. Soon afterward, Grunt became one of the original 13 members.
After the re-dedication of G.I. Joe headquarters, aka "The Pit", Grunt and many of the other original Joes were taken off active duty. Even so, Grunt continued to occasionally participate in missions with the team.